refactor: 重构项目模块结构与代码细节优化

1.  调整后端模块路由与插件文件结构，迁移部分模块代码至api/v1目录
2.  优化代码注释格式与文档字符串，简化冗余代码
3.  添加监控仪表盘、工单评论等新模块功能
4.  修复前端部分组件交互逻辑与类型定义
5.  清理冗余的初始化数据与废弃配置文件
6.  新增租户注册表单字段与国际化支持
7.  优化HTTP请求拦截器与快捷键功能

backend/app/core/event_bus.py

@@ -0,0 +1,101 @@
+"""异步事件总线 — SSE 通知推送的核心组件
+
+职责：
+- 维护每个用户的 asyncio.Queue（用户退出后自动清理）
+- 提供 publish / publish_tenant / subscribe / unsubscribe 接口
+
+使用方：
+- SSE 端点 → subscribe / unsubscribe
+- 各业务服务 → publish / publish_tenant
+"""
+
+from __future__ import annotations
+
+import asyncio
+import json
+from dataclasses import dataclass, field
+from datetime import datetime
+from typing import Any
+
+from app.core.logger import logger
+
+
+@dataclass
+class _Subscriber:
+    """订阅者信息"""
+
+    user_id: int
+    tenant_id: int
+    queue: asyncio.Queue[str] = field(default_factory=lambda: asyncio.Queue(maxsize=256))
+
+
+class EventBus:
+    """异步事件总线（全局单例）"""
+
+    _subscribers: dict[int, _Subscriber] = {}
+
+    @classmethod
+    def subscribe(cls, user_id: int, tenant_id: int) -> asyncio.Queue[str]:
+        """为用户创建一个事件队列（已存在则返回现有队列）"""
+        sub = cls._subscribers.get(user_id)
+        if sub:
+            return sub.queue
+        sub = _Subscriber(user_id=user_id, tenant_id=tenant_id)
+        cls._subscribers[user_id] = sub
+        logger.debug(f"SSE 订阅: user_id={user_id} tenant_id={tenant_id}")
+        return sub.queue
+
+    @classmethod
+    def unsubscribe(cls, user_id: int) -> None:
+        """移除用户的事件队列"""
+        cls._subscribers.pop(user_id, None)
+        logger.debug(f"SSE 取消订阅: user_id={user_id}")
+
+    @classmethod
+    async def publish(cls, user_id: int, event: dict[str, Any]) -> None:
+        """向指定用户推送事件（用户不在线则静默丢弃）"""
+        sub = cls._subscribers.get(user_id)
+        if sub is None:
+            return
+        payload = _build_sse_payload(event)
+        try:
+            await asyncio.wait_for(sub.queue.put(payload), timeout=2)
+        except (TimeoutError, asyncio.QueueFull):
+            logger.warning(f"SSE 推送超时或队列满: user_id={user_id}, event={event.get('type')}")
+
+    @classmethod
+    async def publish_tenant(cls, tenant_id: int, event: dict[str, Any]) -> None:
+        """向租户下所有在线用户推送事件"""
+        payload = _build_sse_payload(event)
+        tasks = []
+        for sub in cls._subscribers.values():
+            if sub.tenant_id == tenant_id:
+                tasks.append(_put(sub.queue, payload))
+        if tasks:
+            await asyncio.gather(*tasks, return_exceptions=True)
+
+    @classmethod
+    async def publish_all(cls, event: dict[str, Any]) -> None:
+        """向所有在线用户广播事件"""
+        payload = _build_sse_payload(event)
+        tasks = [_put(sub.queue, payload) for sub in cls._subscribers.values()]
+        if tasks:
+            await asyncio.gather(*tasks, return_exceptions=True)
+
+    @classmethod
+    def online_count(cls) -> int:
+        """当前在线 SSE 连接数"""
+        return len(cls._subscribers)
+
+
+def _build_sse_payload(event: dict[str, Any]) -> str:
+    """将事件字典序列化为 SSE data 行"""
+    event.setdefault("timestamp", datetime.now().isoformat())
+    return json.dumps(event, ensure_ascii=False)
+
+
+async def _put(queue: asyncio.Queue[str], payload: str) -> None:
+    try:
+        await asyncio.wait_for(queue.put(payload), timeout=1)
+    except (TimeoutError, asyncio.QueueFull):
+        pass